1. Field of the Disclosure
The present disclosure relates to a microlens array, which interconnects a planar lightwave circuit and array of optical semiconductor element such as a photodiode used in an optical communication field, and an optical transmission component including the microlens array.
2. Discussion of the Background Art
A gradient index (hereinafter referred to as GI) multimode optical fiber used in optical communication has a square refractive index distribution in which the refractive index is maximum at the core center and exhibits a good lens function when the optical fiber is used as not only an optical transmission path as a primary role but a microlens. Thus, the optical fiber is used for optical coupling between an optical circuit and an optical semiconductor element such as a photodiode (hereinafter referred to as PD).
FIG. 1 is an example of a conventional type of microlens array used for such an object (for example, see Patent Document 1). In FIG. 1, two arrays of microlenses 1 constituted of a GI fiber and having an optical axis in the Z-axis direction are interposed between a V-shaped groove plate 2 and a top plate 3 so as to be arranged along an array axis parallel to a X axis and are fixed with an adhesive 4. Although the Z direction length of the microlens 1 is different depending on desired light collecting position and light collecting diameter, it is usually approximately 0.3 to 1 mm.
Patent Document 1 Japanese Patent Application Laid-Open No. 2008-040028